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Article: Electrokinetic flows through a parallel-plate channel with slipping stripes on walls

TitleElectrokinetic flows through a parallel-plate channel with slipping stripes on walls
Authors
KeywordsA-plane
Area fraction
Current flux
Slipping surfaces
Electroosmosis
Issue Date2011
PublisherAmerican Institute of Physics. The Journal's web site is located at http://ojps.aip.org/phf
Citation
Physics Of Fluids, 2011, v. 23 n. 10 How to Cite?
AbstractLongitudinal and transverse electrohydrodynamic flows through a plane channel, of which the walls are micropatterned with a periodic array of stripes, are considered. One unit of wall pattern consists of a slipping stripe and a non-slipping stripe, each with a distinct zeta potential. The problems are solved by a semi-analytical method, where the basic solutions satisfying the electrohydrodynamic equations are expressed by eigenfunction expansions, and the coefficients are determined numerically by point collocation satisfying the mixed stick-slip boundary conditions. In the regime of linear response, the Onsager relations for the fluid and current fluxes are deduced as linear functions of the hydrodynamic and electric forcings. The phenomenological coefficients are explicitly expressed as functions of the channel height, the Debye parameter, the slipping area fraction of the wall, the intrinsic slip length, and the zeta potentials. Attention is paid to some particular kinds of patterns, with a view to revisit and to generalize the theoretical limits made in previous studies on electrokinetic flow over an inhomogeneously slipping surface. One should be cautious when applying the theoretical limits. We show that when a surface is not 100% uniformly slipping but has a small fraction of area being covered by no-slip slots, the electro-osmotic enhancement can be appreciably reduced. We also show that when the electric double layer is only moderately thin, slipping-uncharged regions on a surface will have finite inhibition effect on the electro-osmotic flow. © 2011 American Institute of Physics.
Persistent Identifierhttp://hdl.handle.net/10722/142375
ISSN
2015 Impact Factor: 2.017
2015 SCImago Journal Rankings: 1.036
ISI Accession Number ID
Funding AgencyGrant Number
Research Grants Council of the Hong Kong Special Administrative Region, ChinaHKU 715609E
HKU 715510E
University of Hong Kong200911159024
Funding Information:

Financial support was given by the Research Grants Council of the Hong Kong Special Administrative Region, China, through Project Nos. HKU 715609E and HKU 715510E, and also by the University of Hong Kong through the Seed Funding Programme for Basic Research under Project Code 200911159024. Private communications with Professor Martin Z. Bazant and Professor Olga I. Vinogradova, and comments by the referees are gratefully acknowledged.

References
Grants

 

DC FieldValueLanguage
dc.contributor.authorNg, COen_HK
dc.contributor.authorChu, HCWen_HK
dc.date.accessioned2011-10-28T02:44:30Z-
dc.date.available2011-10-28T02:44:30Z-
dc.date.issued2011en_HK
dc.identifier.citationPhysics Of Fluids, 2011, v. 23 n. 10en_HK
dc.identifier.issn1070-6631en_HK
dc.identifier.urihttp://hdl.handle.net/10722/142375-
dc.description.abstractLongitudinal and transverse electrohydrodynamic flows through a plane channel, of which the walls are micropatterned with a periodic array of stripes, are considered. One unit of wall pattern consists of a slipping stripe and a non-slipping stripe, each with a distinct zeta potential. The problems are solved by a semi-analytical method, where the basic solutions satisfying the electrohydrodynamic equations are expressed by eigenfunction expansions, and the coefficients are determined numerically by point collocation satisfying the mixed stick-slip boundary conditions. In the regime of linear response, the Onsager relations for the fluid and current fluxes are deduced as linear functions of the hydrodynamic and electric forcings. The phenomenological coefficients are explicitly expressed as functions of the channel height, the Debye parameter, the slipping area fraction of the wall, the intrinsic slip length, and the zeta potentials. Attention is paid to some particular kinds of patterns, with a view to revisit and to generalize the theoretical limits made in previous studies on electrokinetic flow over an inhomogeneously slipping surface. One should be cautious when applying the theoretical limits. We show that when a surface is not 100% uniformly slipping but has a small fraction of area being covered by no-slip slots, the electro-osmotic enhancement can be appreciably reduced. We also show that when the electric double layer is only moderately thin, slipping-uncharged regions on a surface will have finite inhibition effect on the electro-osmotic flow. © 2011 American Institute of Physics.en_HK
dc.languageengen_US
dc.publisherAmerican Institute of Physics. The Journal's web site is located at http://ojps.aip.org/phfen_HK
dc.relation.ispartofPhysics of Fluidsen_HK
dc.rightsPhysics of Fluids. Copyright © American Institute of Physics.-
dc.rightsCopyright (2011) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in (Physics of Fluids, 2011, v. 23 n. 10, article no. 102002) and may be found at (http://pof.aip.org/resource/1/phfle6/v23/i10/p102002_s1).-
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License-
dc.subjectA-plane-
dc.subjectArea fraction-
dc.subjectCurrent flux-
dc.subjectSlipping surfaces-
dc.subjectElectroosmosis-
dc.titleElectrokinetic flows through a parallel-plate channel with slipping stripes on wallsen_HK
dc.typeArticleen_HK
dc.identifier.emailNg, CO:cong@hku.hken_HK
dc.identifier.authorityNg, CO=rp00224en_HK
dc.description.naturepublished_or_final_version-
dc.identifier.doi10.1063/1.3647582en_HK
dc.identifier.scopuseid_2-s2.0-80155127322en_HK
dc.identifier.hkuros197637en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-80155127322&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume23en_HK
dc.identifier.issue10en_HK
dc.identifier.isiWOS:000296528000008-
dc.publisher.placeUnited Statesen_HK
dc.relation.projectA homogenization-based model for roughness-induced apparent slip-
dc.relation.projectElectrohydrodynamic slip flow through a channel with micropatterned surfaces-
dc.identifier.scopusauthoridNg, CO=7401705594en_HK
dc.identifier.scopusauthoridChu, HCW=36968515700en_HK

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